Recipe 8.26 Program: laston

When you log in to a Unix system, it
tells you when you last logged in. That information is stored in a
binary file called lastlog. Each user has their
own record; UID 8 is at record 8, UID 239 at record 239, and so on.
To find out when a given user last logged in, convert their login
name to a number, seek to their record in that file, read, and
unpack. Doing so with shell tools is hard, but with the
laston program, it's easy. Here's an example:

The program in Example 8-9 is much newer than the
tctee program in Example 8-8,
but it's less portable. It uses the Linux binary layout of the
lastlog file. You'll have to change this for
other systems.